Botryosphaeria Stem Blight

• Stem blight is caused by the fungus Botryosphaeria dothidea, which enters the plant through a wound and travels through the vascular system. Initial symptoms are flagging, or browning of branch tips, and wilting. As the fungus travels down stems toward the ground, more twigs are killed and infected stems develops a dead, crispy look. Symptoms begin to appear in June and continue throughout the summer. Fungal spores are spread during wet spring and fall weather.
  
  

Control

• Prune to remove infected stems. Cut below the infected portion and check the wood for a caramel brown coloration. If you see any brown, disinfect your shears with rubbing alcohol and cut further down the stem. Continue disinfecting and cutting until only healthy, white wood is present at the cut site. Dispose of or destroy infected wood. Avoid using fertilizer after mid-summer. Late applications of fertilizer encourage succulent growth that is easily wounded by frost. Practice good pest management techniques. Injuries caused by insect pests can expose the plant to infection.
  
  

Phomopsis Twig Blight

• Phomopsis vaccinii causes twig blight, a fungal infection that causes significant berry loss. Buds are the first part of the plant to show symptoms as they wither and die. The infection then spreads to twigs, killing them and turning them black. Typically the fungus only kills young, fruit baring growth, but in colder climates, like Michigan and Indiana, it can progress down the stem and cause cankers. Symptoms appear in February and continue through March.
  
  

Control

• Prune infected twigs back to healthy wood. Disinfect your pruning shears with rubbing alcohol between each cut and destroy or dispose of infected wood. Avoid wetting foliage when you water as this can spread the infection. Apply lime sulfur just after bud break to help control the twig blight fungus. Check with your local county extension for current fungicide recommendations in your area.